The invention pertains to methods of incorporating nitrogen into silicon-oxide-containing layers, and in particular application pertains to methods of forming transistors. The invention also pertains to transistor structures.
It can be desirable to incorporate nitrogen into silicon-oxide-containing layers during formation of semiconductor devices. For instance, it can be desirable to incorporate nitrogen into gate oxides (which typically are silicon dioxide) to reduce dopant penetration through the oxides. Methods have been developed wherein nitrogen is incorporated into a gate oxide during deposition of the gate oxide by including nitrogen species amongst the deposited materials. It can, however, be difficult to control nitrogen location within silicon-oxide-containing layers formed by such techniques. Accordingly, it would be desirable to develop alternative techniques for incorporating nitrogen into silicon-oxide-containing layers.
In one aspect, the invention encompasses a method of incorporating nitrogen into a silicon-oxide-containing layer. The silicon-oxide-containing layer is exposed to a nitrogen-containing plasma to introduce nitrogen into the layer. The nitrogen is subsequently thermally annealed within the layer to bond at least some of the nitrogen to silicon within the layer.
In another aspect, the invention encompasses a method of forming a transistor. A gate oxide layer is formed over a semiconductive substrate. The gate oxide layer comprises silicon dioxide. The gate oxide layer is exposed to a nitrogen-containing plasma to introduce nitrogen into the layer, and the layer is maintained at less than or equal to 400xc2x0 C. during the exposing. Subsequently, the nitrogen within the layer is thermally annealed to bond at least a majority of the nitrogen to silicon. At least one conductive layer is formed over the gate oxide layer. Source/drain regions are formed within the semiconductive substrate, and are gatedly connected to one another by the at least one conductive layer.
In yet another aspect, the invention encompasses transistor structures.